Kaihara, U.S. Pat. No. 4,762,389 points out that various kinds of optical fiber connectors are known for connecting two optical fibers and/or an optical fiber and an optical component such as a light emitting, or light receiving element. Kaihara further point out that one type of such connector is a pair of plugs with each fixed to an end of an optical fiber. These connectors include an adapter through which the optical fibers are interconnected with the optical axis of the plugs aligned. When utilized with a light emitting and a light receiving element, the plugs are inserted into a receptacle in which the light emitting or light receiving element is contained.
Various types of connections between adapters and plugs are known, including screw lock types, bayonet locks and the push-on lock type also known as push-pull coupling type. Umeki, et al, Japanese Showa 60-218932 discloses a push-pull coupling type. It includes an adapter equipped with an alignment sleeve and resilient catch pieces. The pieces are in cantilever form with protrusions and a claw attached to the tip of the form. The connector also includes a frame that contains an integrated ferrule and a through passageway from the rear to the front of the ferrule. The frame has protruding parts that are caught by claws of the resilient catch pieces of the adapter. A resilient inner tube shaped in the form of a round tube has an inside diameter almost equal to the outside diameter of the optical fiber cable and an outside diameter almost equal to the hole in the rear portion of the plug frame. A cord tube has a flexible part at its front end which, when inserted into the hole in the rear of the plug frame, is secured to the frame by the bending of the flexible part. The plug frame also has a finger grip mounted on its outside with raised parts. When the ferrule of the plug frame is inserted into or pulled from the alignment sleeve, the raised parts of the plug frame contact the protrusions of the cantilever form and push the resilient claws to the outside allowing the protrusions to pass. The plug frame may have a finger grip housing which is able to slide forward and backward with respect to the plug frame and, additionally, which has raised parts which release the catch of claws on the protruding parts of the plug frame when the finger grip housing is moved backward.
Iwasa, et al, Japanese Showa 62-26141, relates to a duplex type of connector in which a permanent housing provides two alignment sleeves and two ferrules to permanently encompass two optical fibers of the push-pull coupling type of connector. As pointed out by Iwasa, high density mounting of connectors is more readily attainable with such connectors than when two single core optical connectors are utilized. Similarly, Myers, et al, U.S. Pat. No. 4,872,736, relates to a duplex connector encompassed within a release cover to provide a plug of the push-pull coupling type.
Kaihara, et al, U.S. Pat. No. 4,762,389, discloses both a simplex pin-type of plug and a duplex pin plug that includes a cooperative pair of plug holders accommodated within a single housing. This second embodiment comprising the plugs encompassed within a singular permanent housing is advantageous in that it permits simultaneous connect and disconnect of the fiber plugs from the pair of other optical fibers or optical components such as a light emitting and light detecting element.
Advantageous would be the capability of coupling plug holders which have been provided as individual elements within an attachable and detachable overconnector, thereby providing the advantages of the optical fiber connector with dual optical fiber plugs encompassed within a permanent housing as taught by Iwasa, et al, Japanese Showa 62-26141, Myers, et al, U.S. Pat. No. 4,872,736, and by Kaihara, U.S. Pat. No. 4,762,389, to be obtained in the instance where individual optical fiber connectors are provided, each having a single optical fiber plug therein, but in an application that would permit or require a dual connection such as with an optical component having both a light emitting and a light detecting element.
The connector of Kaihara, U.S. Pat. No. 4,762,389, is a push-pull coupling type of connector comprising an optical fiber plug with a the plug including a ferrule for fixing the optical fiber on a center axis thereof. The ferrule has a terminal tip. A spring member is positioned coaxially with the ferrule and along an outer periphery thereof. A slipout-preventing member is fixed to the ferrule for preventing the spring member from slipping out. A first housing accommodates the ferrule, the spring member and the slipout-preventing member. The first housing is provided with a pair of parallel extensions, each extending toward the terminal tip of the ferrule along an opposite side periphery of the ferrule, and a pawl protruding from a tip of each of the extensions toward the center axis of the ferrule. A second housing accommodates the first housing and is slidable a predetermined amount in a direction parallel to the center axis of the ferrule in contact with an outer periphery of the first housing. The second housing is so configured that the pair of parallel extensions snugly fit into the second housing and are prevented from expanding from each other at a position where the second housing is moved forward along the pair of parallel extensions.
The fiber connector of Kaihara also includes an adapter for receiving the optical fiber plug. The adapter includes a block provided with a cylindrical bore for receiving the ferrule. The block has a pair of parallel outer side surfaces which are disposed symmetrically around a center axis of the bore. The block also has a recess provided in a part of its side surfaces. The plug and the adapter are connected by mating the recesses of the block of the adapter with the respective pawls of the first housing while inserting the tip of the ferrule into the cylindrical bore of the adapter. The second housing is then slid into position.
The present invention is an overconnector assembly for a pair of simplex optical fiber connectors, each having a defined exterior profile and structure that operates the simplex optical fiber connectors as a duplex connector. The structure is characterized by easy snap-on connection to a pair of simplex connectors of the push-pull type to thereby form a single body to serve the functions provided with the duplex connector of Iwasa, et al or of Kaihara.
The present invention is an overconnector for a pair of simplex optical fiber connectors which permits the coupling of simplex connectors of the push-pull type. The overconnector of the present invention is characterized by easy snap-on connection to a pair of simplex connectors of the push-pull type to thereby form a single body to serve the functions provided with the duplex connector of Iwasa, et al or of Kaihara.
Gerace, et al, U.S. patent application Ser. No. 07/159,151, published EPC Specification No. 0330399, Aug. 30, 1989, relates to a sheath connector for an optical fiber. This connector may be adapted to a push-pull type connector by a plug housing in two sections with biasing surface and slot for mating with resilient catch pieces of an adapter. The present invention particularly relates to an overconnector assembly for a pair of simplex type connectors that incorporate the Gerace, et al sheath connector.